The subject invention is directed to the art of measuring systems and, more particularly, to display devices such as gauges or the like for visual presentation of associated parameters.
Measuring systems including gauges of the type under consideration are commonly used in the automotive arts to display associated parameters derived from a motor vehicle such as, for example, vehicle speed, engine rotational speed in revolutions per minute, fuel gauge indicia, and other parameters. Typical analog display instruments include a movable indicator needle that is operated by means of an underlying control mechanism such as, for example, a stepping motor or a rotor coil. The indicator needle typically extends adjacent a graduated scale providing indicia of the value range of the parameters of interest. The rotor coil or stepping motor in the underlying measuring system control actuates motion of the movable indicator needle relative to the graduated scale for a representation of the subject parameter.
In many known display systems, separate measuring systems are typically used for the display of each individual parameter. Each separate measuring system includes a set of connection contacts for supplying the respective signals to the measuring system from the corresponding parameters. Also, each measuring system typically includes a separate driven shaft provided in a housing or the like of the measuring system. The driven shaft is typically connected with an indicator needle which is moved relative to a graduated scale in a manner described above.
One problem arises, however, with respect to combination instruments of the type described above. Frequently, the desire to place the required number of measuring systems within the housing of a single combined gauge or instrument presents a space constraint problem. Often, it is desired to arrange the analog displays in close proximity to each other. However, the measuring systems that drive the analog displays often restrict the ability to do so.
One solution to the above problem consists of providing two or more measuring systems with corresponding controls in a single housing together with the use of gears or the like to effect the transfer of rotary motion between an output shaft of the measuring system and the one or more indicator needles. This solution facilitates a more remote arrangement between the respective measuring systems and the controls. Both of these solutions, however, are often costly and are therefore expensive to implement.
It is therefore desirable to provide a measuring system such as an automotive gauge system or the like that is inexpensive, occupies a small space, and has the ability of displaying the status of at least two monitored parameters simultaneously.
The subject invention provides a compact dual integrated gauge system for visual display of at least two associated parameters simultaneously. The gauge system includes first and second intermateable independently operable control devices. The first control device includes a first housing and a first hollow driven shaft extending from the first housing. The second control device includes a second housing and a second driven shaft extending from the second housing. The second driven shaft extends coaxially through the first hollow driven shaft thereby realizing the smallest possible overall construction dimensions of the subject measuring system.
The coaxial arrangement of the two driven shafts extending from two respectively independently actuatable controls enables analog display of at least two parameters within an extremely small area. The present invention conserves on space both with respect to the display elements or the display scales as well as with respect to the measuring system.
In accordance with one aspect of the invention, the measuring system includes at least two separate housings, each of which including a control and a driven shaft. At least one of the driven shafts includes a hollow opening so that the two separate housings can be assembled into a single measuring system in a stacked relationship with the hollow driven shaft of a first individual measuring system being penetrated by the driven shaft of the other individual measuring system. The inner driven shaft is coaxially received in the outer driven shaft with the free end of the inner shaft extending beyond the free end of the outer shaft for ready attachment to a display needle or the like.
In accordance with another aspect of the invention, the two measuring system are substantially identically formed except for the driven shafts and the related components or areas influenced by the shafts. This arrangement is conducive to high volume industrial production resulting in significant cost savings.
In accordance with yet another aspect of the invention, a guide sleeve is disposed on the housing of the second individual measuring system. The guide sleeve supports the second driven shaft of the second individual measuring system. Further, the guide sleeve protects the second driven shaft from movement or the like that may occur in the first hollow driven shaft or the first measuring system.
Similarly, in accordance with another aspect of the invention, a positioning collar is provided at the housing of the first individual measuring system. The positioning collar surrounds and supports the first hollow driven shaft. In addition, the positioning collar provides an installation aid for guiding the first and second driven shafts into a hole or the like of an associated installation component such as a support member or a conductor plate for mounting the assembled subject measuring system in an installed position.
In accordance with yet a further aspect of the invention, the first and second individual measuring systems include electrical connection contacts extending from the first and second housings thereof, respectively. The first individual measuring system includes a first set of electrical contacts extending from the first housing. Similarly, the second individual measuring system includes a second set of electrical connection contacts extending from the second housing. The second set of electrical contacts have a height sufficient to extend in a first direction beyond the first housing and substantially adjacent to the first set of electrical connection contacts when the first and second individual measuring systems are arranged in the preferred stacked relationship to form the assembled subject measuring system. The size and orientation of the sets of electrical connection contacts in this fashion enables electrical connection to the overall measuring system from one side thereof.
In accordance with yet another aspect of the invention, a locking means is provided to enable the selective stacked joining of the first and second individual measuring systems to form the subject dual integrated gauge system.
In addition to the above, the individual measuring systems of the present invention can be connected by means of screws, application of pressure, or the like. In addition, the present invention contemplates initially joining the two individual measuring systems by simply inserting the two driven shafts into each other and then connecting the combination of the two individual measuring systems via screws, holding clamps, or the like to an associated assembly component such as, for example, an associated conductor plate of a combination instrument. In this arrangement, one or more connection contacts of the individual measuring system can penetrate the housing of the other individual measuring system and thereby fix the relative position between the measuring systems.
In accordance with another aspect of the invention, a support member is further provided having separate retaining recesses adapted to receive the first and second individual measuring systems. A guide sleeve is preferably provided at the second individual measuring system for penetrating the support member and engaging the first individual measuring system through the support component. This advantageously results in the benefit that the second individual measuring system is fixed in place relative to the support member by means of the guide sleeve which concurrently serves as a support mechanism for the hollow second driven shaft.
In accordance with yet still a further alternative form of the invention, the support member is eliminated and the guide sleeve of the second individual measuring system is used to engage and support the hollow driven shaft of the first individual measuring system. In addition, the guide sleeve is selectively adapted to provide a means of retaining the individual measuring systems in their relative stacked relationship by means of an appropriate passage aperture provided in the housing of the first individual measuring system.
In a yet further aspect of the invention, the support element includes a locking area for engaging first and second locking means provided on the first and second housing members, respectively. The locking area holds the first and second measuring systems in place relative to the support element. This results in a simple installation of the subject measuring system.
In addition, the support element is further provided with connection means adapted to cooperate with corresponding connection means provided on an associated installation element for fastening and retaining the subject measuring system thereto. These connection means can be formed as locking members, screw connections, crimping connections including assembly pins penetrating the assembly element with pin ends twisted under pressure, or the like.
Still other aspects, advantages, and benefits the invention will become apparent to those skilled in the art upon a reading and understanding of the following detailed description.